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    <div id="app" data-server-rendered="true"><div class="theme-container"><header class="navbar"><div class="sidebar-button"><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" role="img" viewBox="0 0 448 512" class="icon"><path fill="currentColor" d="M436 124H12c-6.627 0-12-5.373-12-12V80c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12z"></path></svg></div> <a href="/" class="home-link router-link-active"><img src="/img/fairwinds-logo.svg" alt="Fairwinds Polaris Documentation" class="logo"> <span class="site-name can-hide">Fairwinds Polaris Documentation</span></a> <div class="links"><div class="search-box"><input aria-label="Search" autocomplete="off" spellcheck="false" value=""> <!----></div> <nav class="nav-links can-hide"><div class="nav-item"><a href="https://github.com/FairwindsOps/polaris" target="_blank" rel="noopener noreferrer" class="nav-link external">
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  <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></div> <!----></nav>  <ul class="sidebar-links"><li><section class="sidebar-group depth-0"><a href="/" class="sidebar-heading clickable router-link-active"><span>Polaris</span> <!----></a> <ul class="sidebar-links sidebar-group-items"><li><a href="/changelog/" class="sidebar-link">Changelog</a></li><li><a href="/code-of-conduct/" class="sidebar-link">Code of Conduct</a></li><li><a href="/contributing/" class="sidebar-link">Contributing</a></li></ul></section></li><li><section class="sidebar-group depth-0"><p class="sidebar-heading"><span>Ways to Run Polaris</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/dashboard/" class="sidebar-link">Dashboard</a></li><li><a href="/admission-controller/" class="sidebar-link">Admission Controller</a></li><li><a href="/infrastructure-as-code/" class="sidebar-link">Infrastructure as Code</a></li></ul></section></li><li><section class="sidebar-group depth-0"><p class="sidebar-heading"><span>Customization</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/customization/configuration/" class="sidebar-link">Configuration</a></li><li><a href="/customization/checks/" class="sidebar-link">Check Settings</a></li><li><a href="/customization/custom-checks/" class="sidebar-link">Custom Checks</a></li><li><a href="/customization/exemptions/" class="sidebar-link">Exemptions</a></li></ul></section></li><li><section class="sidebar-group depth-0"><p class="sidebar-heading open"><span>Checks</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/checks/security/" aria-current="page" class="active sidebar-link">Security</a></li><li><a href="/checks/efficiency/" class="sidebar-link">Efficiency</a></li><li><a href="/checks/reliability/" class="sidebar-link">Reliability</a></li></ul></section></li></ul> </aside> <main class="page"> <div class="theme-default-content content__default"><h1 id="security"><a href="#security" class="header-anchor">#</a> Security</h1> <p>These checks are related to security concerns. Workloads that fail these
checks may make your cluster more vulnerable, often by introducing a path
for privilege escalation.</p> <table><thead><tr><th>key</th> <th>default</th> <th>description</th></tr></thead> <tbody><tr><td><code>security.hostIPCSet</code></td> <td><code>danger</code></td> <td>Fails when <code>hostIPC</code> attribute is configured.</td></tr> <tr><td><code>security.hostPIDSet</code></td> <td><code>danger</code></td> <td>Fails when <code>hostPID</code> attribute is configured.</td></tr> <tr><td><code>security.notReadOnlyRootFilesystem</code></td> <td><code>warning</code></td> <td>Fails when <code>securityContext.readOnlyRootFilesystem</code> is not true.</td></tr> <tr><td><code>security.privilegeEscalationAllowed</code></td> <td><code>danger</code></td> <td>Fails when <code>securityContext.allowPrivilegeEscalation</code> is true.</td></tr> <tr><td><code>security.runAsRootAllowed</code></td> <td><code>warning</code></td> <td>Fails when <code>securityContext.runAsNonRoot</code> is not true.</td></tr> <tr><td><code>security.runAsPrivileged</code></td> <td><code>danger</code></td> <td>Fails when <code>securityContext.privileged</code> is true.</td></tr> <tr><td><code>security.insecureCapabilities</code></td> <td><code>warning</code></td> <td>Fails when <code>securityContext.capabilities</code> includes one of the capabilities <a href="https://github.com/FairwindsOps/polaris/tree/master/checks/insecureCapabilities.yaml" target="_blank" rel="noopener noreferrer">listed here<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></td></tr> <tr><td><code>security.dangerousCapabilities</code></td> <td><code>danger</code></td> <td>Fails when <code>securityContext.capabilities</code> includes one of the capabilities <a href="https://github.com/FairwindsOps/polaris/tree/master/checks/dangerousCapabilities.yaml" target="_blank" rel="noopener noreferrer">listed here<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></td></tr> <tr><td><code>security.hostNetworkSet</code></td> <td><code>warning</code></td> <td>Fails when <code>hostNetwork</code> attribute is configured.</td></tr> <tr><td><code>security.hostPortSet</code></td> <td><code>warning</code></td> <td>Fails when <code>hostPort</code> attribute is configured.</td></tr></tbody></table> <h2 id="background"><a href="#background" class="header-anchor">#</a> Background</h2> <p>Securing workloads in Kubernetes is an important part of overall cluster security. The overall goal should be to ensure that containers are running with as minimal privileges as possible. This includes avoiding privilege escalation, not running containers with a root user, not giving excessive access to the host network, and using read only file systems wherever possible.</p> <p>A pod running with the <code>hostNetwork</code> attribute enabled will have access to the loopback device, services listening on localhost, and could be used to snoop on network activity of other pods on the same node. There are certain examples where setting <code>hostNetwork</code> to true is required, such as deploying a networking plugin like Flannel.</p> <p>Setting the <code>hostPort</code> attribute on a container will ensure that it is accessible on that specific port on each node it is deployed to. Unfortunately when this is specified, it limits where a pod can actually be scheduled in a cluster.</p> <p>Much of this configuration can be found in the <code>securityContext</code> attribute for both Kubernetes pods and containers. Where configuration is available at both a pod and container level, Polaris validates both.</p> <h2 id="further-reading"><a href="#further-reading" class="header-anchor">#</a> Further Reading</h2> <ul><li><a href="https://kubernetes.io/docs/tasks/configure-pod-container/security-context/" target="_blank" rel="noopener noreferrer">Kubernetes Docs: Configure a Security Context for a Pod or Container<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="https://www.youtube.com/watch?v=ltrV-Qmh3oY" target="_blank" rel="noopener noreferrer">KubeCon 2018 Keynote: Running with Scissors<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="https://kubernetes-security.info/" target="_blank" rel="noopener noreferrer">Kubernetes Security Book<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="https://kubernetes.io/docs/tasks/configure-pod-container/security-context/#set-capabilities-for-a-container" target="_blank" rel="noopener noreferrer">Kubernetes Docs: Set capabilities for a Container<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="http://man7.org/linux/man-pages/man7/capabilities.7.html" target="_blank" rel="noopener noreferrer">Linux Programmer's Manual: Capabilities<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="https://kubernetes.io/docs/concepts/configuration/overview/#services" target="_blank" rel="noopener noreferrer">Kubernetes Docs: Configuration Best Practices<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="http://alesnosek.com/blog/2017/02/14/accessing-kubernetes-pods-from-outside-of-the-cluster/" target="_blank" rel="noopener noreferrer">Accessing Kubernetes Pods from Outside of the Cluster<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" 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